Webbing strip-to-tubular frame member fastenings

ABSTRACT

A webbing strip-to-tubular frame member fastening incorporating a clip having general T-configuration provided by a relatively elongated and wide head part and a prong integral with said head part and extending at a substantial right angle from its centrallength portion, the prong having a relatively wide root portion and a pointed end portion formed with oppositely projecting side wings, the relatively outer-upper corner areas of which are bent and/or coined in manner as to provide locking-barb formations characterized by locking edges which face towards the head part and incline downwardly-outwardly and to one side of the general plane of the prong proper, said locking-barb formations upon assembly of the clip being adapted to lock beneath the end corners of the slot in the tubular frame member.

Appl. No.: 444,012

Related U.S. Application Data Continuation-in-part of Ser. No. 207,314, Dec. 13, 1971, abandoned.

References Cited UNITED STATES PATENTS 7/1962 Kramer ..160/404 1/1967 Kramer 160/404 United States Patent [1 1 [111 3,910,339 Kramer Oct. 7, 1975 WEBBING STRIP-TO-TUBULAR FRAME Primary ExaminerPeter M. Caun MEMBER FASTENINGS Attorney, Agent, or FirmJ. Harold Kilcoyne [76] Inventor: Hyman Kramer, Stamford, Conn, [22] Filed: Feb. 20, 1974 [57] ABSTRACT A webbing strip-to-tubular frame member fastening incorporating a clip having general T-configuration provided by a relatively elongated and wide head part and a prong integral with said head part and extending at a substantial right angle from its central-length portion, the prong having a relatively wide root portion and a pointed end portion formed with oppositely projecting side wings, the relatively outer-upper corner areas of which are bent and/or coined in manner as to provide locking-barb formations characterized by locking edges which face towards the head part and incline downwardly-outwardly and to one side of the general plane of the prong proper, said locking-barb formations upon assembly of the clip being adapted to lock beneath the end corners of the slot in the tubular frame member.

5 Claims, 8 Drawing Figures US. Patent \jzd'g HYMA/V KRAMER Oct. 7,1975

WEBBING STRIP-TO-TUBULAR FRANIE MElVIBER FASTENINGS INTRODUCTION This application is a continuation-in-part of application Ser. No. 207,314 filed Dec. 13, 1971, now abandoned.

This invention relates to improvements in flexible strip-to-tubular member fastenings, illustratively but not exclusively webbing strip-to-tubular frame furniture fastenings of the general type disclosed and claimed in my US. Pat. Nos. 3,042,113 dated July 3, 1962, and 3,298,426 dated Jan. 17, 1967, and to an improved prong-type fastener or clip for use in such fastenings.

BACKGROUND OF THE INVENTION Tracing the development of the herein invention, it was earlier suggested that the vertical leg or prong portion of clips constructed according to the earlier of my aforementioned US. Pat. No. 3,042,l 13 could well be strengthened so as to provide the fastening with a greater factor of safety against possible failure when used in tubular-frame furniture applications subjected to rough usage or requiring that the webbing strips secured by the clips be capable of sustaining greater than usual loads. This increased-strength need was'satisfied by the expedient disclosed and claimed in my aforementioned U.S. Pat. No. 3,298,426 of forming the root portion of the clip prong or leg with substantial width as compared to the narrow-width stem or root portion of the clip prong according to my earlier US. Pat. No. 3,024,l 13 and by achieving the desirable locking-barb effect by striking out (cutting) locking barbs in embryo from the side-edge material of said wider and hence stronger root portion and thereupon bending them to their final locking-barb configuration.

While the aforesaid change in the clips locking-barb structure proved highly successful in terms of greater prong strength, as evidenced by the large number of fastenings employing same which are still in use and giving excellent service in heavy-duty applications, it soon became evident that the cost of producing clips characterized by locking-barbs which are incised or struck out from the material (steel strip) of the sideedge portions of the root portions of the prongs was substantially greater than that of producing the fasteners or clips according to my earlier US. Pat. No. 3,042,1 13.

Efficiency studies made to determine the reason for the increased production costs revealed that the cause thereof was in the excessive grind-out time necessary to maintain the cutting edges of the cutters or punches in the sharpened condition necessary to their being able effectively to strike out the locking barbs in embryo from the material of the side-edge portions of the wider root portion of the prong. In explanation, prongtype fasteners or clips of the kind under discussion are conventionally fashioned from hardened steel strip which is fed through a progressive die in a series of uniformly spaced increments of motion. While it is possible to blank out the prong or leg of each clip from the material of the head portion thereof in a simple blanking-out operation capable of being performed in the usual manner, locking barbs in-embryo can be struck out from the material of the side-edge portions of the clip prong or leg only by punch-type cutters whose cutting edges must be maintained in sharp condition. This requirement of course necessitates that the operation of the progressive die be interrupted at frequent intervals and for appreciable periods of time to allow for sharpening of the edges of said cutters (such intervals being known as grind-out time), all of which results in a slowing-down of the manufacturing operation as compared to that required to fashion clips according to the earlier of my aforesaid US. Pat. Nos. 3,042,113 and 3,298,426.

OBJECTS OF THE INVENTION A major object of the present invention therefore is the provision of a fastening of the general type disclosed and claimed in my aforesaid US. Pat. Nos. 3,042,1 l3 and 3,298,426, but which incorporates a fastener or clip characterized by locking-barb formations which are simply bent and/or coined from the material of the side-edge portions of its prong, as distinguished from locking barbs which are punched or cut in embryo from said material.

The invention also contemplates and aims to provide a driveor push-in type of webbing strip-to-tubular frame member fastening incorporating a clip characterized by a clip leg or prong which is so constructed and arranged as to possess great holding power and concomitant resistance to collapse under heavy loads or weights applied to the webbing strip fastened thereby and which is further characterized by having lockingbarb formations constructed and designed as positively to lock beneath the end corners of a slot in the tubular frame member provided for the reception of said leg or prong, responsive to the latter being assembled, i.e. pushed or driven home in the slot.

DETAILED DESCRIPTION OF THE INVENTION The above and other objects and features of advantages of the improved fastening and clip therefor according tothe present invention will be set forth in or appear from the following detailed description thereof taken with the accompanying illustrative drawing wherein I FIG. 1 is a broken-away plan view of a seator backpanel of a tubular-frame type furniture piece fashioned from interlaced fabric or plastic-material webbing strips extending between and being each secured adjacent their opposite end portions to the spaced-apart parallel tubular-frame members thereof by improved fasteners or clips according to the invention (which latter are not seen in the particular view);

FIG. 2 is a transverse section taken along line 22 of FIG. 1 which illustrates each of the webbing strip-totubular frame member fastenings employing a clip of the invention;

FIG. 3 is a view similar to FIG. 2 but illustrating the fastening thereof in perspective;

FIGS. 4, 5 and 6 are respectively under-side plan, front elevational and perspective views of a webbing strip fastener or clip as employed in the fastening shown in FIGS. 2 and 3 (of which FIG. 4 additionally illustrates in broken lines the modified fastener or clip whose prong is slightly angled); and

FIGS. 7 and 8 are fragmentary detail views, of which FIG. 7 attempts to illustrate the manner in which effective locking-barb formations can be and are fashioned from the material of the side-wing portions of a clip prong without any requirement of cutting into, i.e. incising, said material, according to one feature of the present invention; and FIG. 8 is intended to illustrate the locking engagement which said locking-barb edges of the clip prong are designed to make beneath the edges of a frame-member slot at approximately the two longitudinally spaced corners thereof.

Referring to the drawing figures in detail, a webbing strip fastener or clip of the invention, like that of the fastener or clip disclosed and claimed in my aforesaid patents, has general T-configuration when viewed as in FIG. 5. More particulary, it comprises an elongated bar-like head part 10 and integral therewith and extending at an approximate right angle from the middlelength portion thereof a stiff, generally planar leg or prong having a relatively wide root portion 12 and roughly arrowhead-shaped end portion 14 which terminates in a sharply defined point 16. If considered necessary or advisable, the prong may be provided with a longitudinal strengthening rib 22. Preferably, said head part 10 initially has width which is somewhat greater than the overall length of the prong, a feature enabling said, prong to be blanked out and formed complete fromthe width material of the head part. Preferably also, the .head part in transverse section has shallow channel configuration (FIG. 6) which provides it with a generally planar body portion 10:: and longitudinal side-edge flanges 10b, 10c which project therefrom in the same direction as does the prong 12-16. Thus, the head part 10 of a properly designed clip, upon the latter being assembledto a tubular frame member such as that designated 30, will seat thereon in the manner shown in. FIGS. 2 and 3, all as explained in my prior US. Pat. No. 3,298,426 as aforesaid.

In common with the fasteners or clips of both my aforementioned patents, a fastener or clip according to the present invention is by its very design capable of automatically locking itself to a tubular frame member, such as the aforesaid member 30, when assembled thereto as by pushing or driving its pointed prong portion 14 into and thence through the conventionally narrow-width and preferably parallel-sided slot 32 provided in the tubular frame-member wall for the reception thereof. Thus it is possible to effect a secure fastening of a webbing-strip end portion to the frame member 30 by first pre-assembling a clip to a webbing strip as by forcing the point 16 of its prong portion 14 through said strip at a particular location along the length of the stripas provides for an end portion thereof forming a partial wrap about said tubular frame member, and then assembling the pre-assembled clip and webbingstrip end by pushing or driving its pointed prong portion into and through the slot 32 in the frame member as aforesaid.

To achieve the desirable automatic locking of the v clip-to-tubular frame member, the clip prong (12-16),

rather than being provided with locking barbs of the type which were fashioned by incising or cutting into the material of the side-edge portions of the prong proper and then bending the material disposed sidewardly-outwardly of and relatively below said incisions or cuts out of the plane of said prong proper according to my US. Pat. No. 3,298,426 aforesaid, instead is provided with locking-barb formations comprising l) upper-outer corner areas a and b of oppositeiy projecting side wings 18a, 18b formed on the prong-in-embryo during the course of its being blanked outfrom the material of the head part; (2) the relatively upper edges 41,, b, of said corner areas, i.e. the edges which face towards the fastener head part 10 and which by design are spaced a predetermined distance relatively beneath same; and (3) the coined linear indentations a b which incline towards one another from said edges a b and are disposed generally parallel to the converging edges which define the pointed prong portion 14 and terminate in the pront point 16.

Referring to FIG. 7, which is a fragmentary view illustrating in broken lines the general configuration of a prong-in-embryo just after it has been blanked out from the material of the head part 10 and even prior to its point 16 having been fully formed, it is explained that at such illustrated early stage of fabrication the relatively upper edges of the wings 18a, 18b which ultimately provide the aforesaid locking-barb formation edges a b extend substantially co-linearly. However, the subsequently practiced operations of coining the linear indentations designated a 12 into the material of the prong at locations thereof best shown in FIGS. 5 and 6, followed by that of bending the outer-comer areas a, b of said wings out of the plane of the prong proper to the extent as may be necessary to effect pronounced locking-barb formations having locking edges a b which incline outwardly-downwardly from the under surface of the head part 10 and also to one side of the general plane of the prong proper by a small angle, provide that said wing formations 18a, 18b supply a measure of depth or thickness dimension to the prong, such in addition to an appreciable lateral extension thereof beyond the edges of the prong root portion 12.

This depth or thickness dimension which the lockingbarb formations and/or their inclined locking edges 11,, b supply to a clip prong of the invention as aforesaid yields an unexpected advantage, i.e. that of a clip prong of the proper design and dimension relative to the length and/or width of the slot 32 in the tubular wall of the frame member into which the prong will ultimately be pressed or forcibly driven, being capable of making three positive points of contact with the longitudinal side edges of said slot. More particularly, and as attempted to be illustrated in FIG. 8, which is a view taken through the prong of an assembled clip just outwardly of the peripheral plane of a tubular frame member 30 (roughly along section line 8-8 of FIG. 2), the prong, by virtue of its depth dimension which the bentover wing areas supply thereto as aforesaid and which depth dimension can be taken as being slightly greater than the width dimension of the slot 32, is shown to make one point of contact designated x, with one long edge x of the slot and additionally to make two spacedapart points of contact designated y,, y with the other long edge y of the slot. And said latter points of contact y y consequent to the inclination of said locking edges a,, b,, will normally coincide with points along said inclined locking edges, the exact location of which will depend on the width of the slot, the springiness of the material from which the prong is fashioned, and to a degree the thickness of the webbing-strip material, all

factors in determining the amount that the prong can against the prong moving with any degree of freedom either longitudinally or transversely within the slot.

So too, by providing the prong with overall width which is slightly greater than the length of the slot 32, the locking-barb formations of the prong can be made to lock with a snap action beneath the two corners of the slot 32 in which the one longitudinal side edge y terminates. This prong locking barb edge-to-slot corner locking action appreciably supplements the aforesaid three points-of-contact locking action which the prong makes with the long edges x, y of the slot as shown in FIG. 8, and by actual tests both such actions have been found to be more than adequate in insuring that'the prong will lock itself securely to the tubular frame member when pushed, forced or driven into a properly dimensioned slot 32 provided in the wall of the tubular member for its reception.

While the above applies to a fastening incorporating a fastener'or clip whose prong is non-twisted or nonangled with respect to the longitudinal center line of the clip head part as is largely conventional, it applies in great part also to a fastening employing a slightly modified clip-prong structure to be described, following a brief background statement therefor, as follows:

Analysis of FIG. 2 illustrating in transverse section a fully assembled webbing strip-to-tubular frame member fastening of the invention shows that the shortest distance between the aforementioned points of contact y,, y-,, along the inclined locking edges a b (or one of said edges as will hereinafter appear) and the line of contact which the long side-edge flange 100 of the clip head part makes with the periphery of the tubular frame member via the interposed webbing-strip (wrap) is also a factor in the positive locking of the clip to the tubular frame member so that it cannot possibly work itself loose and finally drop away therefrom. Thus, it becomes apparent that the design of the clip should desirably provide that said distance is always such as to draw said flange 10c radially-inwardly, so that it always bears tight against the peripheral surface of the tubular member.

According to the modified clip structure as herein proposed, the aforesaid distance can be simply and effectively shortened by bodily angling i.e. twisting, the prong by a slight angle about its axis, with the result that one of the inclined locking edges a b illustratively the locking edge a,, moves closer to the line of the head-part flange 10c, thereby decreasing the aforesaid distance by the amount of angling imparted to the prong. The degree of angling of the prong, however, is not such as interferes with normal prong insertion through the tubular-member slot 30, and it is a feature of the invention that following full prong insertion, the clip automatically assumes normal position, i.e. straightens itself out within said slot.

The aforementioned slight angling of the prong is attempted to be shown in broken lines (FIG. 4), from which it will be understood that one locking-barb formation 18a thereof and accordingly its inclined locking edge a, will assume a position closer to the longitudinal edge of the fastener head-part, than if the prong was not so angled.

Without further analysis, it will be appreciated that a fastener or clip of the invention and the fastening made possible by its use, all as herein disclosed, achieve in full measure the objectives of the invention stated in the foregoing. However, as many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a webbing strip-to-tubular member fastening, a tubular frame member, a webbing strip having an end portion extending as a partial wrap about said frame member, and a clip securing said webbing-strip end portion to the frame member, said clip comprising an elongated bar-form head part and a prong integral with said head part extending at a substantial right angle therefrom, said prong piercing the webbing strip and projecting through an elongated slot provided for its reception in the wall of the tubular frame member, said prong having overall thickness and width dimensions greater than the width and length dimensions, respectively, of the slot, and said prong including in its thickness dimension locking-barb formations having inclined edges which extend beneath and lock to opposite end corners of the slot.

2. In a fastening according to claim 1, wherein said locking-barb formations comprise wing portions of the prong which extend continuously and oppositely therefrom and whose relatively upper edges provided said inclined edges which extend beneath and lock to end corners of the tubular-member slot.

3. In a fastening according to claim 1, wherein said locking-barb formations comprise wing portions of the prong which extend continuously from opposite sides thereof and inclined, by a predetermined small amount, out of the plane of the prong and whose upper edges provide said inclined edges which lock beneath the end corners of the tubular-member slot.

4. In a fastening according to claim 1, wherein the clip head part has an elongate side-edge formation which bears on and presses the webbing strip tightly to the surface of the tubular frame member, and wherein said locking-barb formations comprise wing portions which extend continuously from opposite sides of the prong proper and whose relatively upper edges provide said inclined edges which extend beneath and lock to the end corners of the tubular-member slot.

5. In a fastening according to claim 4, wherein said prong is bodily angled by a predetermined small amount with respect to the longitudinal line of the sideedge formation of the head part, thereby effecting lessening of the distance between one of said inclined edges and the elongate side-edge formation on the head part. 

1. In a webbing strip-to-tubular member fastening, a tubular frame member, a webbing strip having an end portion extending as a partial wrap about said frame member, and a clip securing said webbing-strip end portion to the frame member, said clip comprising an elongated bar-form head part and a prong integral with said head part extending at a substantial right angle therefrom, said prong piercing the webbing strip and projecting through an elongated slot provided for its reception in the wall of the tubular frame member, said prong having overall thickness and width dimensions greater than the width and length dimensions, respectively, of the slot, and said prong including in its thickness dimension locking-barb formations having inclined edges which extend beneath and lock to opposite end corners of the slot.
 2. In a fastening according to claim 1, wherein said locking-barb fOrmations comprise wing portions of the prong which extend continuously and oppositely therefrom and whose relatively upper edges provided said inclined edges which extend beneath and lock to end corners of the tubular-member slot.
 3. In a fastening according to claim 1, wherein said locking-barb formations comprise wing portions of the prong which extend continuously from opposite sides thereof and inclined, by a predetermined small amount, out of the plane of the prong and whose upper edges provide said inclined edges which lock beneath the end corners of the tubular-member slot.
 4. In a fastening according to claim 1, wherein the clip head part has an elongate side-edge formation which bears on and presses the webbing strip tightly to the surface of the tubular frame member, and wherein said locking-barb formations comprise wing portions which extend continuously from opposite sides of the prong proper and whose relatively upper edges provide said inclined edges which extend beneath and lock to the end corners of the tubular-member slot.
 5. In a fastening according to claim 4, wherein said prong is bodily angled by a predetermined small amount with respect to the longitudinal line of the side-edge formation of the head part, thereby effecting lessening of the distance between one of said inclined edges and the elongate side-edge formation on the head part. 